During an operation of a crane, in particular in case of remote hoisting operation or crossing operation over a certain obstacle, due to a visual error of the operator, an accurate position of the object to be hoisted cannot be precisely determined. If the object deviates from the crane hook in the vertical direction, “slant pulling” would occur, which would cause damages to the crane, or even cause an overthrow accident.
At present, hoist of a large-scale weight usually needs careful on-site investigation and calculation. Job conditions including boom extension length, boom pitch angle and the like are estimated in advance. Moreover, at the operation site, the hoisting operation needs command and dispatch by field staff, and is completed by means of visual measurement and experience of the operator. The field operation usually needs coordination by multiple persons through repeated adjustments, which increases uncertainty and hoisting duration of the operation. In particular in case of a complex operation condition such as at night and in a rainy and snowy weather, the difficulty in command and operation by the field staff is increased.
The existing technology mainly has the following two shortcomings:
Firstly, the wireless positioning precision of the object point is low. Since high-precision wireless positioning is not opened, and only civil pseudocodes are available, the precision for the object point positioning is about 10 m. The boom extension length and the boom pitch angle as calculated differ greatly from the actual dimensions, and it cannot be determined accurately the accurate position of the object. If the object deviates from the crane hook in the vertical direction, “slant pulling” would occur, which would cause damages to the crane, or even cause an overthrow accident.
Secondly, execution action by the boom is unclear. In the existing solutions, the execution action by the boom mainly depends on command and dispatch by field staff, and is completed by means of visual measurement and experience of the operator. In case of an operation condition with remote hoisting or crossing over a certain obstacle, due to a visual error of the operator, an accurate position of the object to be hoisted cannot be precisely determined. The hoisting height and hoisting angle are fully determined by visual measurement and experience, which increases the risk.